Electric-arc lamp.



No.744,130. PATENTED NOV. 17, 1903. E. THOMSON.

ELECTRIC ARC LAMP.

APPLICATION FILED MAY 21, 1901.

N0 MODEL.

Elihu Thcivr wson WITNESSES- Noam; PETERS co. vncruumo.v wAsrslNGTDN, a. p.

is bound by the clutch.

UNITED STATES Patented November 1'7, 1903.

PATENT OEEIcE.

EIill-IU THOMSON, OF S\VAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NE\V YORK.

ELECTRIC-ARC LAM F.

SPECIFICATION forming part of Letters Patent No. 744,130, dated November 1'7, 1903.

Applitation filed May 21,1901. Ser al No. 61.302. the model.)

To a, whom, it may concern:

Be itknown that I, ELIHU THOMSON, a citizen of the United States, residing at Swamp seott, county of Essex, State of illassachusctts, have invented certain new and useful Improvemei'its in Arc-Lamps, of which the following is a specification.

In many forms of arc-lamps the opening of the clutch requires force to be exerted by the derived-circuit magnets in opposition to the action of the series magnet or magnets. The force thus required to open the clutch is variable and depends upon circumstances such, for example, as the friction of the parts and the firmness with which the carbon itself The variable pull thus required of the derived circuit or differential magnets, which are in shunt to the are, therefore gives rise to irregular voltages and are lengths.

It is one of the objects of my present invention to secure definite and positive feed of the carbons or other electrodes, thereby preventing the possibility of an abnormal are due, for example, to a sticky clutch or to the fact of the clutch itself reaching the feeding-point and taking off weight from the mechanism, thereby sustaining the are until the derived-circuit magnet has acquired power sufficient to forcibly open the clutch.

The features of novelty of my invention will be particularly pointed out in the claims appended hereto, while the details and mode of operation of the invention itself will be set forth more at length in the following description, which is to be taken in connection with the accompanying drawings, in which- Figure 1 is a view of an arc-lamp embodying my invention, and Figs. 2 and 3 detail views of parts thereof.

I have shown my invention as applied to an arc-lamp of the differential type suitable for use 011 series constant-current circuits. The series magnet, which acts toseparate the carbons and strike the arc, is indicated at 1. This magnet or magnets, as the case may be, cooperates with the differential magnet or magnets 2, connected in shunt across the terminals of the lamp, which terminals are indicated at 3 and 4..

A pivoted armature 5 cooperates with paraher which carries the armature 5. 'oted member which carries the armature 7 boloidal ends 6 of the cores ofthe series magnet or magnets 1. In a similar manner a pivoted armature 7 cooperates with simi]arly-shapcd core ends of the derived-circuit magnet Fig.2 shows somewhat more clearly the arrangement of these pivoted armatures. The armature 5 is indicated in Fig. 2 by the corresponding numeral and will be seen to include two openings 8 and 9, which are intended to cooperate with corresponding cores, only one of which appears in the view in Fig. 1, since the other being directly behind the first is concealed thereby. The armature 7 is likewise indicated in Fig. 2, and both of these armatures are carried by forked members, (indicated, respectively, at 8 and 9,) the arms of the forks being pivoted together, as indicated at 10.

Returning to Fig. 1, it will be seen that the armature 5 carries the clutch-rod11,the upper end of which is pivoted to the armature and the lower end to the jaw 12 of the clutch, the other member of which consists of a ring 13, surrounding the carbon or other electrode 14. Integral with the ring 13 is an upwardly-extending arm 15, the top end of which, 16, is bent over so as to engage upon its downward movement a fixed contact 17, which serves the double purpose of completing an electric circuit and of tripping the lamp-clutch. This contact 17 is carried by but insulated from the lamp-frame and is connected electrically to an insulated contact-piece 18, carried bya downwaidly-extending arm 19, this arm being joined mechanically to the pivoted mem- The pivhas a similar downwardly-extending arm 20, which carries in its turn an insulated contact 21, this contact being connected electrically, as shown, with the terminal 3 of the lamp. Fig. 3 is a side view showing the downwardlyextending arms 19 and 20. These arms, as will be seen, are urged apart by a compression-spring of moderate force.

Current as it enters the lamp passes through the terminal 3, through the series winding 1, and then to a plate 23, forming a portion of the lamp-frame. The depending rods 24 and 25, which carry the lower carbon and cooperating mechanism, are, however, insulated from this plate, as shown at 26 and 27. From the plate 23 the current passes through the flexible conductor 28 to the carbon 11, thence to the lower carbon 29, and out of the lamp at the terminal 1. Upon starting the lamp the hooked or overturned end 10 of the upwardly-extending arm 15 of the clutch member 13 rests upon the fixed contact 17, the contacts 21 and 18 being at the same time held apart through the instrumental ity of the spring As soon as current passes through the series magnet the armature 5 is attracted, thereby closing the jaw 12 of the clutch and separating the carbons. As the carbons separate the voltage at the terminals of the derived-circuit magnet 2 increases correspondingly, thereby increasing the power of the magnet, which acts in opposition to the magnet 1. The opposing forces of these two 111 agnets compress the spring 22 and bring the contacts 18 and 21 together, after which the carbons continue to separate until the forces of the series and derived-circuit magnets come into equilibrium. As the carbons slowlyburn away the derived-circuit magnet temporarily increases in strength and causes a feeding together of the carbons until equilibrium is again reached this process resulting in a gradual lowering of the upper carbon. This lowering continues until the hooked or overturned end 16 of the clutch mechanism makes contact with the fixed contact 17. This contact completes a short circuit about the series magnet 1, which thereupon instantly loses its power, and the derived-circuit magnet 2 being no longer opposed by the force of the series magnet immediately causes a vigorous and positive downward thrust of the cl utch-carrying rod 11, which thereupon trips the clutchjaw 12 and allows the upper carbon to drop into contact with the lower carbon, Whereupon the derived-circuit magnet is deenergized, contacts 18 and 21 open by the spring 22, and the series magnet 1 is again brought into action, after which the operation is again repeated when the parts again reach the feed ing-point.

The purpose of the spring-separated contacts 1S and 21 is to enable the lamp to start when the clutch is in its lowest position. In this position the contacts 16 and 17 are together and were it not for the spring-separated contacts would maintain a short circuit about the starting-magnet. After the lamp starts the contacts 18 and 21 automatically close, thereby permitting the proper action of the contacts 16 and 17 when the feeding-point is reached, as has been described above.

lVhat I claim as new, and desire to secure by Letters Patent of the United States, is-

1. In an electric-arc lamp, the combination of an arc-striking magnet in series with the are, a derived circuit magnet tending to shorten the are, a shunt-circuit about the arcstrilcing magnet, and means for maintaining said circuit open when the electrodes of the lamp are together and for closing it when the electrodes are about to feed together.

2. In an electric-arc lamp, the combination of an arc-strikin g magnet, a clutch mechanism controlled thereby, and means for shunting said magnet as the clutch mechanism commences to trip.

The combination of electrodes, a clutch mechanism for one of said electrodes, a mag net cooperating with the clutch mechanism for separating said electrodes, and means for deenergizing said magnet when the clutch mechanismis at one of the limits of its movement.

1. In an electric-arc lamp, the combination of electrodes, a magnet for separating said electrodes, and means for deenergizing said magnet as the electrodes are about to feed together and re'energizing the magnet as the electrodes come together.

5. In an electric-are lamp, the combination of a series magnet, clutch mechanism con trolled thereby, a derived-circuit magnet cooperatively related to the series magnet, and means controlled both by said magnets and said clutch mechanism for closing a circuit about said series magnet.

0. The combination of electrodes, a clutch mechanism operatively related to one of said electrodes, a magnet for operating said clutch mechanism, means for shunting said magnet when said clutch mechanism reaches the feedingpoint, and means for opening said shuntcircuit or maintaining it open when said electrodes are in contact.

7. The combination of electrodes, a clutch mechanism operatively related to one of said electrodes, a series magnet, a derived-circuit 1n agnct for controlling said clutch mechanism, and a plurality of circuit-closing devices in series with a circuit in shunt to said series magnet, one of said circuit-closing devices being controlled by the position of the clutch mechanism and another by the opposing force exerted between said series magnet and said derived-circuit magnet.

8. I11 an electric-arc lamp, the combination of a series magnet, a derived-circuit magnet, and cooperating contacts controlled respecti vely by said magnets and in a shunt-circuit about said series magnet.

9. In an electric-arc lamp, the combination of a series winding, a derived-circuit winding, and means dependent upon the cooperative action of current in said windings .l'or withdrawing current from the entire series winding.

In witness whereof Ihave hereunto set my hand this 18th day of May, 1901.

ELIIIU THOMSON.

IVitncsses:

DUGALD McK. MeKn'mor, JOHN J. WALKER. 

